Since it sounds like you have younger kids, I'd take a decent sized portion of it (maybe 2-8k) and use that to make lasting family memories. Seeing everything of interest in a short range (zoos, aquariums, caves, gardens, museums, national parks, whatever), more frequent small vacations (driving distance or short flights to the beach/mountains/whatever), occasional major vacations (other countries, theme parks, cruises, whatever your family finds interesting). Or investing in lifelong hobbies that you can do together, like skiing, art, tennis, restoring cars, etc.
After that, the rest I would add to my FIRE plan. It would not necessarily mean retiring sooner (though it might), but it would be about adding flexibility to my life. If my savings were larger, I could always just to dip into that to pay for college or I be better prepared to deal with an unexpected layoff or emergency.